JPH04219710A - Zoom lens device - Google Patents

Abstract

PURPOSE:To achieve a short time shifting to the initial position by controlling a stepwise shifting means so that a variable power lens group may be shifted to the position of a position detecting sensor in the initial operation. CONSTITUTION:When a switch is turned on, control of initialization is realized by an operation control part 17. The initial position is adjusted so that the position information of a variable power lens group 2 may agree with the data stored in the storage by changing the position of a photo-reflector and the value of the predetermined voltage. Setting the variable power lens group 2 to the initial position allows the operation control part 17 to shift the variable power lens group 2 by the subsequent pushing of a zoom operation button. Then, a focusing lens group 4 is shifted to a focusing position corresponding to the shift of the variable power lens group 2 on the basis of the combined data of the position information of the lens group 2 which is obtained from the pulse count of the shifted pulse motor 24 and the data read from the storage.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a zoom lens device, and more specifically, the present invention relates to a zoom lens device, in which a variable power lens group and a focusing lens group are moved by motors that are each driven and controlled by an arithmetic control means. The present invention relates to a zoom lens device in which a focusing lens group is moved to a focusing position based on positional information of a focusing lens group.

0002

[Prior Art] As a zoom lens device as described above,
A device shown in the schematic diagram of FIG. 8 is known. In this zoom lens device, 1, 3, and 5 are fixed lens groups, 2 is a variable power lens group, 4 is a focusing lens group, and 6 is a zoom lens group.
and 7 are a low-pass filter and image sensor for focus detection,
8 and 9 are holding frames for the variable power lens group and focusing lens group, respectively; 10 and 11 are screws that move the holding frames 8 and 9 in the optical axis direction; and 12 are screws that move the screw 10 via a gear train 13; A DC motor rotates the screw 11 in forward and reverse directions, 14 is a pulse motor that is a stepping motor that rotates the screw 11 in forward and reverse directions, 15 and 16 are drive circuits for the DC motor 12 and pulse motor 14, respectively, and 17 is a drive circuit 15, respectively.
, 16, a calculation control unit that controls the rotation of the DC motor 12 and the pulse motor 14; 18, a potentiometer that outputs position information of the variable magnification lens group 2 to the calculation control unit 17 in conjunction with the holding frame 8; 19; is a light shielding plate 9 integrated with the holding frame 9
20 is a signal processing circuit that processes the output signal of the image sensor 7; 21 is a focusing circuit; The focal signal detection circuit 22 is an aperture device.

In this zoom lens device, when a power switch (not shown) is turned on, the pulse motor 14 is operated by the drive device 16 until the arithmetic control section 17 inputs the moving end position information of the focusing lens group 4 from the photo interrupter 19. It is driven to bring the focusing lens group 4 to the initial position of the moving end on the near-distance side or the far-distance side. Thereby, the arithmetic control unit 17 initializes an internal counter so that the number of pulse counts of the pulse motor 14 that moved the focusing lens group 4 from the initial position is used as the position information of the focusing lens group 4. become On the other hand, the positional information of the variable power lens group 2 is inputted from the potentiometer 18 to the arithmetic control unit 17 by turning on the power switch, regardless of initialization.

When the above-mentioned initialization is performed and the photographing switch (not shown) is turned on, the arithmetic control section 17 drives the pulse motor 14 via the drive device 16 based on the output information of the focus signal detection circuit 21. to move the focusing lens group 4 to the focusing position. The positional information of the focusing lens group 4 necessary for this movement is obtained by counting the above-mentioned counter.

Furthermore, when the wide side or telephoto side of a zoom operation button (not shown) is pressed, the arithmetic control unit 17 causes the variable power lens group 2 to move through the drive device 15 if it is not at the widest side or the most telephoto side. The DC motor 12 is driven to move the variable power lens group 2 to the wide-angle side or the telephoto side. The arithmetic control unit 17 also calculates the combinations of the positions of the zooming lens group 2 and the focusing lens group 4 that are in focus for various distances from infinity to close range, which are stored in the storage device, and the potentiometer 18. The combination of the position of the variable power lens group 2 given by the lens group 2 and the position of the focusing lens group 4 given by the pulse counter is compared, and the combination of the position of the variable power lens group 2 given by the potentiometer 18 is then focused. In order to change the position of the focusing lens group 4, the pulse motor 14 is driven via the drive device 16 to move the focusing lens group 4 to the focusing position.

The movement of the variable power lens group 2 and the accompanying movement of the focusing lens group 2 described above are based on information that the variable power operation button is released or when the variable power lens group 2 is at the wide end or telephoto end. Needless to say, it will be stopped depending on the information that reaches its location.

This zoom lens device uses a DC motor 12
Since the gear train 13 is required to transmit the rotation of the camera to the screw 10, there are problems in that the number of parts increases, the number of assembly steps increases, the cost increases, and space is required to prevent downsizing of the camera. Furthermore, since the position of the variable magnification lens group 2 is detected by the potentiometer 18, there is a problem in that the frictional resistance is large, increasing the load on the DC motor, and the reliability of operation at low temperatures decreases. In order to solve the problem caused by the contact sensor, using a non-contact sensor to obtain position information over the entire movement range of the variable magnification lens group 2 would not only increase costs but also increase the accuracy of position detection. also decreases.

Therefore, in order to solve the above-mentioned problem, the variable magnification lens group 2 is moved by a stepwise moving means in the same way as the focusing lens group 4, and the number of steps moved from the initial position is counted. A zoom lens device that can obtain position information has been invented. However, with this zoom lens device, it takes time for the variable power lens group 2 to be brought to the initial position and initialized when the power switch is turned on.
There was a problem in that people sometimes lost photo opportunities.

[0009]

[Problems to be Solved by the Invention] The present invention uses a stepwise moving means to move the variable power lens group, and obtains position information of the variable power lens group by counting the number of steps moved from the initial position. This was done in order to solve the above-mentioned problem in the zoom lens device, and the zoom lens group is moved to the initial position in a short time during the initial operation such as when the power switch is turned on. To provide a zoom lens device that can quickly start photographing operation.

0010

[Means for Solving the Problems] The present invention provides a variable power lens group, a stepwise moving means for moving the variable power lens group, and an arithmetic control means for controlling the stepwise moving means. In the zoom lens device, a position detection sensor for detecting the position of the variable power lens group is provided at a position approximately at the center of a movement range for variable power of the variable power lens group, and
The zoom lens device is characterized in that the arithmetic control means controls the stepwise moving means to move the variable magnification lens group to the position of the position detection sensor and perform initial setting during initial operation, This configuration achieves the above object.

[0011]

[Operation] That is, in the zoom lens device of the present invention, the variable power lens group is moved by a stepwise moving means, and the position detection sensor of the variable power lens group is moved approximately within the movement range of the variable power lens group. The arithmetic control means controls the stepwise moving means to move the variable power lens group to the position of the position detection sensor at the time of initial operation, so that the variable power lens group moves to the initial position of the variable power lens group. This has the effect that the movement of the camera is carried out in a short time, so that the timing of photographing is not lost, and the apparatus can be constructed simply, compactly, and inexpensively.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments shown in FIGS. 1 to 7.

FIG. 1 is a schematic configuration diagram showing an example of the zoom lens device of the present invention, and FIG. 2 is a plan view of a reflective marker used to detect that the variable power lens group is at the center of the moving range. , Fig. 3 is a graph showing an example of the output change of a photoreflector that detects a reflective sign, and Fig. 4 shows the initial position of the variable magnification lens group of the arithmetic control unit when the photoreflector shows the output change shown in Fig. 3. FIG. 5 is a graph showing another example of the output change of the photoreflector, and FIGS. 6 and 7 are the calculation control unit when the photoreflector exhibits the output change shown in FIG. 5. 2 is a control flowchart of the initialization operation of FIG.

In FIG. 1, the same reference numerals as in FIG. 8 indicate the same functional members or parts, and 24 indicates the drive circuit 15.
A pulse motor 8a is driven by a pulse motor that rotates the screw 10 in forward and backward steps, and 8a is a variable motor 8a which is provided with a reflective mark such as the one shown in FIG. The detected part 28 of the magnification lens group holding frame 8 receives the reflected light from the reflective mark of the detected part 8a, and the variable power lens group 2 moves between the telephoto end T position and the wide end W position. Then, the photoreflector outputs a voltage as shown in FIG. 3 or FIG. 5 accordingly. FIG. 3 shows an example in which the output voltage change curves of the photoreflector 28 match when the variable power lens group 2 moves from the telephoto end T side to the wide end W side and when it moves in the opposite direction.
FIG. 5 shows an example of non-matching.

In the zoom lens device described above, when the power switch (not shown) is turned on, the arithmetic control section 17 performs the initialization control shown in FIG. 4 in the example of FIG. 3, as will be described later. In the example of No. 5, the initialization control shown in FIG. 6 or 7 is performed, and the variable power lens group 2 is moved to the initial position where the output voltage of the photoreflector 28 becomes approximately the predetermined voltage V, that is, the variable power lens The group 2 is brought to a predetermined position in the center of its movement range. From turning on this power switch, the variable magnification lens group 2
Compared to when the initial position is set to the tele end T or wide end W, the time it takes for the lens to stop at the initial position is approximately 1/2, since the average moving distance of the variable power lens group 2 is 1/2.
It will be done in a short time. Therefore, it is possible to prevent the photographing timing from being lost because it takes time to bring the variable power lens group 2 to the initial position.

The control shown in FIG. 4 by the arithmetic control unit 17 is performed when the output voltage change of the photoreflector 28 does not show a hysteresis change as shown in FIG.
1 whether it is initially on the tele end T side or on the wide end W side.
When the output voltage of the photoreflector 28 changes to cross a predetermined voltage V during the pulse movement, the initial position is reached, and at that time, the variable magnification lens group 2 is stopped and the pulse counter is initialized. This is how it was done. With this control, the initial position where the variable power lens group 2 stops is as shown in Figure 3.
M position or a constant position near it. This initial position can be adjusted by changing the position of the photoreflector 28 and the value of the predetermined voltage V so that the positional information of the variable power lens group 2 matches the data stored in the storage device. Since the variable power lens group 2 can be brought to the initial position accurately in this way, when the variable power lens group 2 is subsequently moved by pressing the zoom operation button, the arithmetic control unit 17 will move the variable power lens group 2 from the initial position. The focusing lens group 4 is magnified based on the positional information of the magnification lens group 2 obtained by counting the number of drive pulses of the pulse motor 24 that moved the magnification lens group 2 and the combination read from the storage device. The lens group 2 is moved to a focused position corresponding to the movement of the lens group 2.

The control shown in FIG. 6 by the arithmetic control section 17 is performed when the output voltage change of the photoreflector 28 shows a hysteresis change as shown in FIG. ΔM of hysteresis change shown in 5
In order to prevent the variable magnification lens group 2 from changing
moves from the telephoto end T side to the wide end W side by one pulse, so that the output voltage of the photoreflector 28 becomes the predetermined voltage V.
When the voltage changes from the above state to lower than V, it is assumed that the initial position at the center of the moving range has been reached, and at that time, the variable magnification lens group 2 is stopped and the pulse counter is initialized. . In Fig. 6, the reason why "when the photoreflector output reaches a high level H, the lens group 2 is driven to the predetermined pulse telephoto side" is because it moves the variable power lens group 2 away from the area where the hysteresis change ΔM occurs. This is to ensure that the lens is moved to the telephoto end T side.Therefore, with the subsequent control to "drive the lens group 2 to the wide side one pulse at a time", the output voltage of the photoreflector 28 changes according to the downward arrow on the left side of Fig. 5. As a result, the variable magnification lens group 2 stops at the Mt position or a certain position in the vicinity thereof.

The control shown in FIG. 7 by the arithmetic control unit 17 similarly moves the variable power lens group 2 from the wide end W side to the telephoto side T side in order to prevent the initial position from changing by the hysteresis change ΔM. The time when the output voltage of the photoreflector 28 changes from a voltage below a predetermined voltage V to a voltage exceeding a predetermined voltage V due to movement by one pulse is assumed to be the time when the initial position at the center of the movement range is reached, and the magnification is changed at that time. This is to stop the lens group 2 for use. In this case, the initial position of the variable power lens group 2 is at the Mw position in FIG. 5 or a fixed position near that position.

In both the control shown in FIGS. 6 and 7, the initial position of the variable power lens group 2 can be adjusted in the same manner as described in the control shown in FIG. However, it may be said that one of the Mt position and Mw position in FIG. 5 is relatively stable, and the other position is likely to fluctuate. In that case, Figure 6 and Figure 7
Of these controls, the one that provides a stable center position may be adopted.

[0020]

[Effects of the Invention] In the zoom lens device of the present invention,
A stepwise moving means is used to move the variable magnification lens group, and a position detection sensor for the variable magnification lens group is provided at approximately the center of the movement range of the variable magnification lens group. Since the stepwise moving means is controlled so that the zoom lens group is moved to the position of the variable power lens group position detection sensor, the moving means for the variable power lens group is simple, and the device can be constructed compactly and inexpensively. This provides an excellent effect in that the variable power lens group is brought to the initial position in a short time during the initial operation, eliminating the risk of losing a photographic opportunity.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of the zoom lens device of the present invention, FIG. 2 is a plan view of a reflective marker used to detect the position of a zoom lens group, and FIG. 3 is a photo frame for detecting the reflective marker. A graph showing an example of a change in the output of a reflector. Fig. 4 is a flowchart of the control operation for bringing the variable magnification lens group of the arithmetic control unit to the initial position when the photoreflector shows the change in output shown in Fig. 3. Fig. 5 shows a reflective sign detected. 6 and 7 are flowcharts of the control operation of the arithmetic control unit to bring the variable power lens group to the initial position when the photoreflector exhibits the output change shown in FIG. 5, respectively. , FIG. 8 is a schematic configuration diagram showing an example of a conventional zoom lens device.

[Explanation of symbols]

1, 3, 5...fixed lens group, 2...variable lens group, 4...focusing lens group, 6
...Low pass filter, 7...Image sensor,
8... Lens group holding frame for variable magnification, 8a... Arm to be detected,
9... Focusing lens group holding frame, 9a... Light shielding plate,
10, 11...screw, 12...DC motor,
13... Gear train, 14, 24... Pulse motor,
15, 16... Drive circuit, 17... Arithmetic control unit,
18... Potentiometer, 19... Photo interrupter, 20
...signal processing circuit, 21...focus signal detection circuit, 2
2... Aperture device, 28... Photo reflector.

Claims (3)

[Claims] 1. A zoom lens device comprising: a variable power lens group; a stepwise moving means for moving the variable power lens group; and an arithmetic control means for controlling the stepwise moving means. A position detection sensor for detecting the position of the variable power lens group is provided at a position approximately in the center of the movement range for variable power of the variable power lens group, and the arithmetic control means detects the position of the variable power lens group during initial operation. A zoom lens device characterized in that the stepwise moving means is controlled to move the lens group to the position of the position detection sensor and perform initial setting. 2. The variable power lens group and the focusing lens group are moved by motors each driven and controlled by an arithmetic control means, and the focusing lens group is moved based on the position information of the variable power lens group. In a zoom lens device that moves to the focus position, the output changes depending on whether the variable power lens group is in the center of the movement range, on the telephoto side, or on the wide side. A non-contact variable magnification lens group sensor that changes the output in response to changes in the position of the variable magnification lens group when the group is in the center, a step-type motor for moving the variable magnification lens group, and a step motor for moving the variable magnification lens group. The arithmetic control means moves the variable power lens group to a predetermined center position based on the output information of the sensor at the time of initial operation using a counter for the number of steps driven by the step motor. 1. A zoom lens device, characterized in that control is performed using the count number of the counter, which counts the number of steps of a stepping motor that moves the variable magnification lens group from the center position, as position information. 3. The output information of the sensor for stopping the variable power lens group at the center position during the initial operation is information obtained when the variable power lens group is moved to one of the telephoto side and the wide side. 2. A zoom lens device according to claim 1.